The present invention relates to an image forming apparatus wherein, even when using a lens-fitted film unit whose lens performance is relatively poor and a digital camera, the lens performance can be properly compensated for by processing after photographing, and to a manufacturing method of a lens-fitted film unit in which a function to compensate lens performance is provided as well as to the lens-fitted film unit.
When compared with a lens shutter camera and a single-lens reflex camera which are of the middle class or higher, lens-fitted film units sometimes tend to be inferior in terms of performance because they need to be manufactured at a lowest cost. In addition, in the field of lens-fitted film units, there is a severe competition to make them as small as possible, which makes a sacrifice of the performance.
With regard to performance of a photographic lens, for example, a distortion of a lens-fitted film unit is 5% or less, while that of a lens shutter camera and a single-lens reflex camera which are of the middle class or higher is 3% or less, lateral chromatic aberration of the former is 0.03 mm while that of the latter is 0.1 mm or less, and marginal light quantity for the former is 30% or less while that for the latter is 25% or less, which has been undeniable as a difference in the performance. Incidentally, problems similar to the problems mentioned above are caused also in a digital camera employing an inexpensive lens.
Further, with regard to marginal light quantity for strobe (a difference of quantity of light between the center and the periphery), it was 0.5 EV or less for a lens shutter camera and a single-lens reflex camera which are of the middle class or higher, while it was 1 EV or less for a lens-fitted film unit.
Though there is also available a lens-fitted film unit in which scenery of a tourist resort is photographed on the first frame in advance before shipment, this is nothing but one which simply provides a picture postcard to a user, and this image information is not utilized for processing of prints.
It is impossible, from a viewpoint of cost, for a lens-fitted film unit to have performance similar to that of a lens shutter camera and a single-lens reflex camera which are of the middle class or higher, and a lens-fitted film unit having that performance is hard to be made small. It is therefore possible not to cast a burden upon a lens-fitted film unit, if it is realizable that a lens and a strobe each having relatively poor performance are used for photographing and those performances are compensated in the subsequent processing of prints.